This invention relates to basteriostatic compositions used in metal working such as cutting and grinding of metals.
It is known that aqueous metal working liquid contains, as an effective component, organic compound and hence is deteriorated or decomposed by bateria or molds. In fact, microorganismes which enter into a working liquid utilize organic oil compounds in the working liquid as a nutritive substance and multiply gradually, resulting in the putrefaction of the oil components. Therefore, an antiseptic agent is added to the working liquid to prevent it from such putrefaction. It is a recent trend to develop anti-microorganismes type metal working liquids as well as to improve the performance of the working liquid.
Examples of the antiseptic agent are organic nitrogen-containing compounds such as triazines, thiazines, isothiazolines such as Keson (trade name) and pyrizines. Phenol type compounds and boron type compounds are also envisaged.
Generally, an aqueous working liquid or coolant is poured onto a working point and is recycled. The aqueous working liquid, however, deteriorates gradually, resulting in a foul odor, the bacteria of pH which causes corrosion, as well as in a decrease of lubrication efficiency. The most serious problem is clogging of piping caused by generation of slime (mold).
The known antiseptic agents mentioned above are useful to solve the problems. However, they are not perfect insofar as they are deficient in at least one of areas of corrosion, decomposition, odor foam and waste liquid. Therefore, there is a demand to develop a bioactive type aqueous working liquid which can solve the problems, is harmful to the human body and the environment and which is easy to manage.